1. Field of the Invention
This invention relates to block copolymers of polyphenylene oxides and sterically-hindered aromatic polycarbonates. These block polymers can be molded, calendered, or extruded as films, sheets, fibers, laminates or other useful articles of manufacture.
2. Description of the Prior Art
Low molecular weight bis(polyphenylene)-carbonate block copolymers having limited carbonate segment number average molecular weights, e.g. 250 to 5500, are well known and are described in D. M. White's U.S. Pat. No. 3,875,256. These polyphenylene oxide aromatic carbonate block copolymers are formed by the reaction of carbonyl halides or bishaloformates, e.g., phosgene or bis-chloroformates, respectively, with polyphenylene oxide in the presence of a hydrogen halide acceptor e.g., an alkali metal hydroxide, an alkaline earth metal hydroxide or oxide or a tertiary amine.
Monofunctional polyphenylene oxides having an average hydroxy group per molecule of 1.0 or less, are described in A. S. Hay's U.S. Pat. Nos. 3,306,979; 3,914,266; and 4,028,341, etc., among others.
Polyfunctional polyphenylene oxides having an average hydroxy group per molecule greater than zero including 2.0 or less are described in D. M. White's U.S. Pat. Nos. 4,140,675 and 4,234,706 among others.